whales

In a Peruvian desert, scientists discovered the fossils of an extinct whale with a big bite. The whale's teeth and jaws were so powerful that it feasted on other whales.

Marine mammals live in a world of sound. In the open ocean, whales and dolphins depend on sound waves, using echolocation to navigate, find food, attract mates and communicate. But their clicks and calls are not the only noises underwater: Oil and gas exploration, seafloor mapping, and ship and submarine navigation have increased dramatically over the past few decades, making the world’s oceans noisier than ever.

Millions of years ago, the first animals emerged from their watery habitat to live on dry land. After becoming fully adapted to a terrestrial environment, however, some animals, such as whales, ultimately returned to the ocean. But the evolutionary steps involved in that watery return have long been a mystery. Now, some exceptional fossils — and one really old baby — are shedding some light on how whales went back to the sea.

In the depths of the ocean, the bizarre beaked whale looks more like an eerie mutant than a gentle giant. With its bird-like beak and sharp tusks that jut out from the top of its head, anyone would wonder: What’s with all the weaponry? Now scientists think they’ve found the purpose of these weird tusks — and it is not nearly as maleficent as you may think.

According to conventional wisdom, things that need to move efficiently through air or water should be sleek and streamlined. Dolphins, jets and Olympic swimmers stick to this rule, but humpback whales, with their massive knobby-edged flippers, buck the trend.

The extent of Arctic sea ice shrinks each year during the northern hemisphere’s spring and summer, trading a white frozen surface for dark open ocean. Reaching its lowest annual extent by September or October, the ice grows back again through the cold and dark winter months.